The group of neatly coiffed middle-aged Spanish ladies who had trooped in to Malaga University's sports hall applauded wildly when, to cries of "You can do it!", People's party (PP) leader Mariano Rajoy walked on to the stage.

They had come to see the man who, barring last-minute disasters, will become Spain's prime minister at 20 November elections. But after listening to only part of his speech the 50 or so women filed out again, uninterested in what he had to say. "We are not going to choose the best, so we might as well choose the least worst. That is Rajoy," another woman at a rally in northern La Coruña told television station La Sexta.

Bespectacled, bearded and boring, Rajoy is further hampered by a slight lisp and a tendency to appear more ponderous than prime ministerial on television. Even his own followers admit Rajoy fails to excite many of the Spaniards who are so fed up with the outgoing Socialist government of José Luis Rodríguez Zapatero that opinion polls give his party a 15-point lead. "He will be a good prime minister," says one PP deputy. "But he is not a good candidate. He is much better close-up and we often say that if he could just sit down for coffee with every single Spaniard, then he would win them all over."

Those who know the 56-year-old well warn against underestimating a man they describe as a pragmatic conservative with an iron will and political nerves of steel. They are qualities that will be needed as Rajoy readies to take over the reins of government as the worst economic crisis for decades looks set to hit Spain. Unemployment is already at 23% and growth has slowed to zero. Recession is around the corner and Spain risks being forced to leave the euro. Exactly what he will do, however, largely remains a mystery. Rajoy is a master of ambiguity who has been accused of disguising his plans in order to avoid scaring voters and repeating the mistakes of a fellow European conservative who failed to win an absolute majority – David Cameron. The former land registrar from the rain-soaked, north-western region of Galicia has, instead, waited patiently for the economic crisis to sink Zapatero's socialists, who have embraced austerity, slashed public spending, cut civil service pay and frozen pensions. But that has not cured Spain's ills, with the European commission predicting this week that there will be no pickup in employment until 2013.

Rajoy is not above political trickery. At a television debate with his socialist opponent, former deputy prime minister Alfredo Pèrez Rubalcaba, this week Rajoy made a show of confusing his name with that of Zapatero. It was an unsubtle attempt to tell viewers that Rubalcaba and Zapatero — who is deeply unpopular and decided not to stand again — were one and the same thing.

A former deputy prime minister, Rajoy had run several ministries before prime minister Josè Maria Aznar handpicked as his successor when he stood down in 2004. He came within days of becoming prime minister in elections that year as polls predicted a PP victory. But radical Islamists killed 191 people with bombs planted on Madrid commuter trains a few days before the elections. Aznar, obsessed by Basque terrorist group Eta, blamed the latter instead. Voters punished the PP for that, and for supporting the highly unpopular war in Iraq, by voting in Zapatero.

It is not the kind of mistake Rajoy would make. "He doesn't put ideology first," said a PP deputy. "At heart he is a pragmatist and a provincial conservative," said one Rajoy watcher, pointing to his comfortably middle-class childhood in the Galician city of Pontevedra.

Rajoy's political canniness is best judged by his ability to survive as party leader, despite losing two elections in a row, rather than by the way he opposed Zapatero. That opposition involved four years of railing against Zapatero's social reforms – including gay marriage, abortion on demand and looser divorce laws – before leading his party towards what he called the "moderate centre".

Rajoy had his hands full, meanwhile, seeing off challenges from party grandees backed by an excitable rightwing press who accused him of spending too much time smoking cigars in his office or watching sports on the television.

Although there has been no whiff of corruption to Rajoy himself, he also had to ride out a series of scandals that hit PP regional governments in Valencia, the Balearic Islands and Madrid.

Rajoy stuck to his guns, waiting for Zapatero to bury the socialists on his own. "He can be very obstinate," says one Rajoy-watcher. "He is good at long-term strategies. A crisis that needs swift decision-making may be trickier for him."

Even his critics, however, recognise that Rajoy is his own man, distancing himself from Aznar and resisting the financiers, newspaper editors and others who have sought to co-opt him.

Rajoy believes in balanced budgets and admires Germany's Angela Merkel, and is in tune with the current masters of Spain's destiny – those in Brussels, Berlin, Paris and Frankfurt who run the troubled eurozone. He has pledged to meet strict EU-set deficit reduction targets and promised major economic reform, though he has given few details. Opponents claim this means cuts to basic services and unemployment subsidies as well as fewer labour rights. "That is what he is hiding," said a senior socialist.Rajoy, however, insists he can maintain standards in health, education and pensions while turning the economy around by lowering business taxes.

As a social conservative he has pledged to tighten up the abortion law so that 16-year-old girls can no longer keep abortions secret from their parents. He will leave the constitutional court – where his party challenged Zapatero's gay marriage law – to decide on whether the latter should be rewritten.

Rajoy has little time for Spain's indignado protesters who took to Spanish squares demanding change to a system dominated by just two parties earlier this year. They are, he believes, anti-system radicals. "There are worries, though, that they will turn into an anti-PP movement as soon as the elections are over," admits another PP deputy.

His pledge to lower taxes squares uneasily with his determination to meet deficit targets. Many economists, indeed, believe he will be forced to raise taxes.

That may require his to employ another stereotypical skill attributed to some Galicians – of doing one thing while persuading people he is actually doing the opposite.